The Pantheon is one of the greatest spiritual buildings of the world. It was built as a Roman temple and later consecrated as a Catholic Church. Its monumental porch originally faced a rectangular colonnaded temple courtyard and now enfronts the smaller Piazza della Rotonda. Through great bronze doors, one enters one great circular room. The interior volume is a cylinder above which rises the hemispherical dome. Opposite the door is a recessed semicircular apse, and on each side are three additional recesses, alternately rectangular and semicircular, separated from the space under the dome by paired monolithic columns. The only natural light enters through an unglazed oculus at the center of the dome and through the bronze doors to the portico. As the sun moves, striking patterns of light illuminate the walls and floors of porphyry, granite and yellow marbles. No one knows the Pantheon’s exact age. One legend says that the first Roman citizens built the original Pantheon on the very site where the current one still stands in the Campo Marzo – modern Rome’s business district. The ancients constructed this first Pantheon after Romulus, their mythological founder, ascended to heaven from that site. They dedicated it to Romulus and some of his divine ancestors and, for centuries, held rites and processions there.